Germer



Jan. 31, 1956 E, GERMER ELECTRIC DISCHARGE DEVICE Filed Jan. 25, 1951 INVENTo/e. bMz//vo f/QME/P rug,

United States Patent() 2,733,373 Y ELECTRIC DISCHARGE DEVICE Edmund Germer, Berlin-Wannsee, Germany, assignor to Hanovia Chemical & Mfg. Co., Newark, N. J., a corporationv of New JerseyV This invention relates to electric discharge devices and; isxconcernedl in particular with high pressure vapor dischargelamps and with arrangements for the electrodes and terminals in such lamps.

When electric discharge lamps of the high pressure tube type are manufactured according to the present art in the quantities required by industry, it is found that some of the lamps emit radiations of varying intensities along the length of the tube, i. e., they operate with an unequal distribution of radiations between the ends of the tube. Others operate with a substantially equal distribution of radiations. The lamps exhibiting unequal light distribu tion are not suited for applications requiring control on E the radiation intensity. I do not know why in the manufacture of a number of such lamps according to a set scheme, some of them should turn out with unsatisfactory intensity characteristics. It should bel noted also that even some of those lamps that are found uponinspection to have substantially equal intensity characteristics along the length `of the tube, later develop a deficiency in radiation intensity at one of the ends thereof. Whatever may be the explanation for these occurrences, it is, of course, de-

,sirable that the lamps be so constructed that their light distribution characteristics may be improved when found necessary.

The complete failure of lamps of such type is usually due to the failure of the electrodes or of the lead-in conductor connecting an electrode to a contact terminal of the lamp. The electrodes or the conductors may become broken or the electrodes may in time become less active whereby the lamp will not longer function in the manner for which it was designed.

4 It is a general object of the invention to provide an electric discharge lamp having a substantially longer useful life than lamps of such type manufactured heretofore. Another object is to provide a lamp which when manufactured in large quantities have few if any rejects due to unequal light emanation along the length thereof. Further objects and various advantages will appear from the following detailed description, taken in connection with the accompanying drawing in which:

Fig. l is a view, partly in section, of a vapor discharge lamp constructed according to the invention, and

Fig. 2 is a sectional view taken on line 2-2 of Fig. l and in the direction of the arrows.

The lamp illustrated in said drawing comprises a tubusuch as quartz, closed at each end thereof to provide a In each end of the chamber is a pair of electrodes 7 and 8 supported on the lead-in conductors 9 and 10 which are vacuum tightly sealed in the press seals 11 and 12 in the end walls of the tube 5. The chamber 6 contains the usual starting gas, such as argon, xenon, or krypton, and a sucient amount of vaporizable metal, e. g. mercury, so that during operation, the lamp will develop an internal pressure in excess of about one atmosphere depending upon the wattage desired.

Mounted over each of the ends of the tubular envelope 5 is a plug assembly 13 that is suitably dimensioned to pass into a socket (not shown) whereby the lamp maybe supported between two sockets and energized through an electrical circuit in a known manner. The plug assembly 13 includes a tubular sleeve 14 one end of which telescopes over the end of the envelope 5 with an annular gasket 15 between the adjacent walls of the envelope and the sleeve. The other end of ythe sleeve 14 supports the base 16 of the plug assembly, said base being formed of electrical insulation material, such as, for example, ceramic material and the like. The base 16 is constructed as a cylinder with an annular flange -17 that fits into the sleeve 14 and is supported iirmly in the end of the sleeve between the annular recess 19 and the anged end Ztl of the sleeve.

The cylindrical base 16 is provided with an axial bore 21 having a shoulder 22 on the inner end thereof. Within the bore 21`is a contact Vspring 23 that is electrically connected to the lead-in conductor 10. The other of leadin conductors, i. e. conductor 9, passes dirough a second bore 24 .inthe base 16 and is electrically connected to a metal cap 25 that is firmly fitted over the outer end of the base.

Electrical contact with the spring 23 and the lead-in conductor 10 is provided by means of a contact terminal comprising a metal plate 26 having a conical stem 27 integral with and perpendicular to `one side of the plate. The'stem 27 is dimensioned to extendfor a substantial distance into the bore 21 Where it forms the electrical connection with the spring 23 and is held in the bore by the pressure exerted by said spring. A hole 28 is formed in the cap 25 to accommodate the stem 27, and the hole is made to have a larger diameter than that of to expose the cap 25 which will then carry the current from the socket to the lead-in conductor 9 and to the electrode In. lamps of the type herein contemplated it is common practice to form the electrodes of several thin sheets of a suitable metal having activating compounds between the sheets. Also, it is common practice to form -the electrodes with a iiat circular base plate. and a flanged edge around the rrim of such base plate, thereby providing a receptacle-like construction for the electrodes. In the lamp illustrated in the drawing the electrodes are formed of several layers of such thin sheets and constitute semi-circular receptacles that are spaced apart whereby a maximum portion of each of tne electrodes is located near the axis of the tube to cause the discharge arcs to be substantially centrally located within the tube.

While I have described the invention more specifically with reference to a high pressure vapor discharge lamp, it will be noted that the invention is equally applicable to other types of vapor discharge lamps, e. g. a gerinicidal tricall insulation closing the outer end of said sleeve,v an

or lluorescent lamp having a gaseous or metal vapor lilling, or both.

The foregoing disclosure is to be regarded as descriptive and illustrative only and not as restrictive or limitative of the invention, of which obviously an embodiment may be constructed without departing from the general scope herein indicated and denoted in the appended claims.

What I claim is:

1. ln an electric discharge lamp having a tubular en velope of vitreous material closed at its ends to provide a chamber, subject to unequal distribution of radiations along the envelope, said chamber containing a rare gas anda vaporizable metal, two main electrodes and a leadin conductor for each of said electrodes in each end of said chamber, the electrodes in one end being spaced from the electrodes in the other end of said chamber for supporting a discharge arc therebetween, said conductors extending through the nearest of the end walls of said 35 envelope and being sealed therein, a sleeve telescoped over each end of said tubular envelope and extending beyond its respective end of said envelope, a plug of elecaxial bore in said plug, a spring in said bore electrically connected to one of said conductors, a second bore through said plug, a metal cap covering the outer end of said plug, the other of said conductors passing through said second bore and being electrically connected to said cap, a hole in said cap aligned withV said axial bore, an insulation disc covering said cap, a contact plate covering said disc, and a stem integral with said plate and passing through said disc and the hole in said cap and into said axial bore for contacting said spring, whereby there is provided a means for the non-concurrent operation of the two` electrodes at each end of the chamber-and the arc discharge between the ends of the chamber rnay be made to follow anyone of at least tour paths only one path being obtained for operation at anyone time for each of the aforesaid conductor connections.

2. In an electric discharge lamp according to claim l wherein each of said electrodes is semicircular inconstruction with the diameters'being parallel to each other.

References Cited in theflle of this patent UNITED STATES PATENTS 1,644,744 Pingen Oct. 11, 1927 1,877,832 Meyer et al Sept. 20, 1932 2,097,261 Spanner Oct. 26, 1937 2,116,702 Kern et al. May 10, 1938 2,154,550 White et al Apr. 18, 1939 2,212,881 Lec'orquillier Aug. 27, 1940 2,264,055 Stocker Nov. 25, 1941 2,264,081 Jost et al. Nov. 25, 1941 2,411,679 Cox Nov. 26, 1946 2,513,091 Frohock June 27, 1950 FOREIGN PATENTS 431,763 Great Britain 1935 527,940 Great Britain Oct. 18, 1940 589,240 Great Britain June 16, 1947 

1. IN AN ELECTRIC DISCHARGE LAMP HAVING A TUBULAR ENVELOPE OF VITREOUS MATERIAL CLOSED AT ITS ENDS TO PROVIDE A CHAMBER, SUBJECT TO UNEQUAL DISTRIBUTION OF RADIATIONS ALONG THE ENVELOPE, SAID CHAMBER CONTAINING A RARE GAS AND A VAPORIZABLE METAL, TWO MAIN ELECTRODES AND A LEADIN CONDUCTOR FOR EACH OF SAID ELECTRODES IN EACH END OF SAID CHAMBER, THE ELECTRODES IN ONE END OF BEING SPACED FROM THE ELECTRODES IN THE OTHER END OF SAID CHAMBER FOR SUPPORTING A DISCHARGE ARC THEREBETWEEN, SAID CONDUCTORS EXTENDING THROUGH THE NEAREST OF THE END WALLS OF SAID ENVELOPE AND BEING SEALED THEREIN, A SLEEVE TELESCOPED OVER EACH END OF SAID TUBULAR ENVELOPE AND EXTENDING BEYOND ITS RESPECTIVE END OF SAID ENVELOPE, A PLUG OF ELECTRICAL INSULATION CLOSING THE OUTER END OF SAID SLEEVE, AN AXIAL BORE IN SAID PLUG, A SPRING IN SAID BORE ELECTRICALLY CONNECTED TO ONE OF SAID CONDUCTORS, A SECOND BORE THROUGH SAID PLUG, A METAL CAP COVERING THE OUTER END OF SAID PLUG, THE OTHER OF SAID CONDUCTORS PASSING THROUGH SAID SECOND BORE AND BEING ELECTRICALLY CONNECTED TO SAID CAP, A HOLE IN SAID CAP ALIGNED WITH SAID AXIAL BORE, AN INSULATION DISC COVERING SAID CAP, A CONTACT PLATE COVERING SAID DISC, AND A STEM INTEGRAL WITH SAID PLATE AND PASSING THROUGH SAID DISC AND THE HOLE IN SAID CAP AND INTO SAID AXIAL BORE FR CONTACTING SAID SPRING, WHEREBY THERE IS PROVIDED A MEANS FOR THE NON-CONCURRENT OPERATION OF THE TWO ELECTRODES AT EACH END OF THE CHAMBER AND THE ARC DISCHARGE BETWEEN THE ENDS OF THE CHAMBER MAY BE MADE TO FOLLOW ANY ONE OF AT LEAST FOUR PATHS ONLY ONE PATH BEING OBTAINED FOR OPERATION AT ANY ONE TIME FOR EACH OF THE AFORESAID CONDUCTOR CONNECTIONS. 